In a conventional rotor for a rotary electric machine, in order to prevent a permanent magnet from peeling away from a rotor core due to centrifugal force generated as the rotor rotates, the permanent magnet is provided on an outer peripheral portion of the rotor core, and the rotor core and permanent magnet are covered as a whole from an outer side of the permanent magnet with a fiber-reinforced plastic holding member (see PTL 1, for example).
Further, when PWM (Pulse Width Modulation) control employing an inverter is executed on a rotary electric machine used for high-speed rotation, harmonic magnetic flux is generated from a carrier frequency component such that eddy currents are generated in the rotor core and the permanent magnet, and as a result, the rotor generates heat. When the rotor generates heat, the temperature of the permanent magnet increases, and as a result, demagnetization occurs in the permanent magnet.
In a conventional rotor for a rotary electric machine proposed in the prior art, heat generation by the rotor is suppressed by disposing a cylindrical high-conductivity member having a higher conductivity than other constituent members, such as a permanent magnet and a shaft, between the permanent magnet and a holding member. In this conventional rotor for a rotary electric machine, eddy currents are generated in the high-conductivity member, and magnetic flux generated by the eddy currents cancels out the harmonic magnetic flux of the carrier frequency component. Hence, eddy current generation in the permanent magnet and the rotor core is suppressed, and as a result, demagnetization of the permanent magnet is suppressed (see PTL 2, for example).
In another rotor for a rotary electric machine proposed in the prior art, manufacture is facilitated by dividing a cylindrical high-conductivity member disposed between a shaft and a permanent magnet into a plurality of conduction portions arranged in a circumferential direction (see PTL 3, for example).